The present invention relates to pulse width modulation control. More specifically, it is concerned with software based improvements in the resolution of a PWM control output.
PWM control of electromechanical devices including motors and solenoids is well known. Such control is used to vary the speed and torque output of DC motors, and the response time, position and force of solenoid controlled actuators. The reactive characteristics of the particular load being driven by the PWM controller allows for the achievement of discrete output states for the particular load; for example, a discrete number of speeds for a DC motor and a discrete number of actuator positions corresponding to a respective stroke positions of a biased solenoid plunger.
The granularity or resolution of the device output states depends upon the resolution of the PWM output used to control the device. For a given range of output states, higher resolution in the PWM translates into higher resolution of the device being controlled thereby. Resolution enhancements have typically relied upon hardware alterations on the controller side to provide for more PWM states at the output. However, such hardware based approaches are typically fraught with significant cost penalties and use of non-standardized componentry.